'91 Dodge Spirit Blown Head Gasket?

Maintenance/Repairs
1

This car has high miles - just over 200,000. It has been a good runner.



For a while, coolant has been disappearing. I was hoping it was a simple leak, but could not find evidence of leakage. The coolant loss has been getting worse - and I’ve kept topping it off.



Suddenly the engine began running very rough. I found that one cylinder is completely dead (pulled off the plug wire with it running and it made no difference on that cylinder). I swapped spark plugs etc. to no avail - and then I checked compression on that cylinder - it is ZERO.



So does this sound like a blown head gasket? Is there anything else I can do to confirm before I proceed with a repair? Any tips on doiing a head gasket on this engine? (2.0l 4 cylinder)



Thanks!

2

This is a very common problem with this engine (it’s a 2.5L, BTW). Here’s a good guide for diagnosing and replacing the headgasket:
http://www.allpar.com/eek/headgasket.html

3

Yeah, I’d say that zero compression in one cylinder is a pretty good sign of a trashed head gasket. Take a look at your oil and be sure that coolant hasn’t been getting into there (it would look milky, and/or have the consistency of a milkshake). If you see evidence of this, I’d be concerned about how it’s affected your main bearings which do not like to be washed with antifreeze. Hopefully the coolant has simply been getting burned in the combustion chamber(s), though you’d probably be seeing some serious clouds of white smoke from the exhaust.

4

Hmm… one cylinder being at zero but the adjacent cylinders being normal (are they?) doesn’t sound like a typical blown head gasket. Usually a head gasket leak isn’t big enough to drop the compression all the way to zero. What did the spark plug you pulled out look like? Any whiteish deposits on it?

A zero compression condition is more commonly caused by a valve that isn’t sealing. If I were you, my next step would be to pull the valve cover off and turn over the engine by hand and make sure all the valves are moving when they’re supposed to and that nothing is obviously loose. If that looks good, you’ll have to pull the head-- once you’ve got it off, you’ll be able to tell if you’ll need a valve job or just a head gasket, although it sounds like you probably need a gasket anyways.

5

One additional diagnostic step would be to pressurize that cylinder with compressed air. Get the piston to Top Dead Center; keep the crankshaft from moving; apply the air pressure (40 psi ought to be enough); and listen for where it is going. Intake = valve, tail pipe = valve, cooling system = head gasket or cracked head, crankcase = head gasket, bad rings, or broken piston.

Hope that helps.

6

The oil is fine. No rising level or milky color. So I think the coolant has been going out the exhaust. I don’t drive the car so I can’t vouch for the exhaust, although it did look white to me. I am going to proceed…

7

Either way, the head will still have to come off to change the exhaust valves and clean the intake valves. Even though I like to say get rid of the car, it can still be fixed. Don’t skip too many steps while the head is off or you will look like the people on the V-8 commercial.

8

I don’t know if the other cylinders are “normal”, but they ARE firing. The plug is just wet with gas. I like your suggestion of pulling the valve cover and checking the valves. I’ll do that for sure.

9

What do the people on the V-8 commercial look like ??!

10

DOH… i shoulda had a… (insert here what ever you shoulda done) while whacking forehead in 'tupidity

11

I pulled the valve cover this afternoon and found one of the rocker arms just laying on the head. I have no idea why it came off, but it explains my problem.

Here is a photo: http://www.geocities.com/scoostraw/valves.jpg

The rocker seems undamaged: http://www.geocities.com/scoostraw/rocker.jpg

I am a bit out of my element here. I’ve done timing belts, fixed air conditioners etc. - but never worked on a valve train. Should I try just popping the rocker back in and adjust ??

Or…??

12

You have some good responses to the thread you started over at Allpar.com. Those guys know these engines inside and out.

13

I would recommend that you get new head bolts. It is risky to reuse them.

When I changed the head gasket in my 93 sundance, I left the intake and exhaust manifolds on the head and pull everything together. It’s heavy, but saves some work.

14

If I were you, I’d go ahead and pull the head and do the head gasket, since it does sound like you will need to eventually. You could try to reinstall the rocker, but it’s kind of tricky with everything installed, but would be very easy with the head off.

If you do try to put it back together, make sure you have all of the parts, especially the locknut on the adjuster screw.

15

I agree.

Tonight I loosened the cam, put the rocker back in, and torqued everything back down. It started and runs perfectly. It’s not my car, so I told her to drive it EASY! We’ll see what happens.

Thanks to all for the feedback…

16

I could have had a V-8. Good idea to put it back in and try again. You don’t have to pull the head off now. Back to my original post. I guess that looking first is better than getting a new car.

17

Here it is a year later than your posted note, and I have the same thing going on. Pulled the valve cover and the rocker arm was just laying there. Put it back in place and it ran fine for a while. Until it fell out again. Why? What did yours do? How did you solve this?